question_answer 1)
A mass of 1 kg is attached to the end of a spring with a stiffness 0.7 N/mm. The critical damping coefficient of the system is:
A)
1.40 Ns/m done
clear
B)
52.22 Ns/m done
clear
C)
52.92 Ns/m done
clear
D)
529.20 Ns/m done
clear
View Solution play_arrow
question_answer 2)
Two heavy rotating masses are connected by shafts of lengths \[{{l}_{1}},{{l}_{2}}\] and \[{{l}_{3}}\] and the corresponding diameters are \[{{d}_{1}},{{d}_{2}}\] and \[{{d}_{3.}}\]this system is reduced to a torsionally equivalent system having uniform diameter \[''{{d}_{1}}''\] of the shaft. The equivalent length of the shaft is:
A)
\[\frac{{{l}_{1}}+{{l}_{2}}+{{l}_{3}}}{3}\] done
clear
B)
\[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{3}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{3}}\] done
clear
C)
\[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{4}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{4}}\] done
clear
D)
\[{{l}_{1}}+{{l}_{2}}+{{l}_{3}}\] done
clear
View Solution play_arrow
question_answer 3)
The equation of free vibrations of a system is \[\ddot{x}+36\,\,{{\pi }^{2}}X=0.\] Its natural frequency is:
A)
\[46\text{ }Hz\] done
clear
B)
\[3\,\,\pi Hz\] done
clear
C)
\[3\text{ }Hz\] done
clear
D)
\[6\,\pi Hz\] done
clear
View Solution play_arrow
question_answer 4)
Which of the following methods can be used to determine the damping of machine element?
1. Logarithmic method 2. Band-width method 3. Rayleigh method 4. Holzer method, Select the correct answer using the codes given below:
Codes:
A)
1 and 3 done
clear
B)
1 and 2 done
clear
C)
3 and 4 done
clear
D)
1, 3 and 4 done
clear
View Solution play_arrow
question_answer 5)
If \[\frac{\omega }{{{\omega }_{n}}}=\sqrt{2}\] where \[\omega \] is the frequency of excitation and \[{{\omega }_{n}}\] is the natural frequency of vibrations, then the transmissibility of vibrations will be:
A)
0.5 done
clear
B)
1.0 done
clear
C)
1.5 done
clear
D)
2.0 done
clear
View Solution play_arrow
question_answer 6)
A slender shaft supported on two hearings at its ends carries a disc with an eccentricity e from the axis of rotation. The critical speed of the shaft is N. If the disc is replaced by a second one of the same weight but mounted with an eccentricity 2e, critical speed of :he shaft in the second case is:
A)
\[\frac{1}{2}N\] done
clear
B)
\[\frac{1}{\sqrt{2}}N\] done
clear
C)
N done
clear
D)
2N done
clear
View Solution play_arrow
question_answer 7)
An axial flow fan balanced at one speed often exhibits substantial vibrational effect when operated at other speeds, mainly due to:
A)
Primary critical speed effect done
clear
B)
Secondary critical speed effect done
clear
C)
Unbalanced parts of the fan done
clear
D)
Aerodynamic unbalance done
clear
View Solution play_arrow
question_answer 8)
For a disc mounted shaft to rotate with light side of disc out: Where \[\beta =\frac{\omega }{{{\omega }_{c}}}\]
A)
\[\beta <1\] done
clear
B)
\[\beta =1\] done
clear
C)
\[\beta >1\] done
clear
D)
\[\beta <<1\] done
clear
View Solution play_arrow
question_answer 9)
When shaking force is transmitted through the spring, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than:
A)
0.25 done
clear
B)
0.50 done
clear
C)
1.00 done
clear
D)
sqrt 2 done
clear
View Solution play_arrow
question_answer 10)
When the mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, it will:
A)
Return to equilibrium position without oscillation done
clear
B)
Oscillate with increasing time period done
clear
C)
Oscillate with decreasing amplitude done
clear
D)
Oscillate with constant amplitude done
clear
View Solution play_arrow
question_answer 11)
Under logarithmic decrement, the amplitude of successive vibrations are:
A)
constant done
clear
B)
In arithmetic progression done
clear
C)
In geometric progression done
clear
D)
In logarithmic progression done
clear
View Solution play_arrow
question_answer 12)
The danger of breakage and vibration is maximum:
A)
Below critical speed done
clear
B)
near critical speed done
clear
C)
Above critical speed done
clear
D)
none of the above done
clear
View Solution play_arrow
question_answer 13)
With symbols having the usual meanings, the single degree of freedom system, \[m\ddot{x}+c\dot{x}+kx=F\sin \,\,\omega t\] represents:
A)
Free vibration with damping done
clear
B)
Free vibration without damping done
clear
C)
Forced vibration with damping done
clear
D)
Forced vibration without damping done
clear
View Solution play_arrow
question_answer 14)
A simple spring mass vibrating system has a natural frequency of N. If the spring, stiffness is halved and the mass is doubled, then the natural frequency will become:
A)
N/2 done
clear
B)
2N done
clear
C)
4N done
clear
D)
8N done
clear
View Solution play_arrow
question_answer 15)
Rotating shafts tend to vibrate violently at whirling speeds because:
A)
The shafts are rotating at very high speeds done
clear
B)
Bearing centre line coincides with the shaft axis done
clear
C)
The system is unbalanced done
clear
D)
Resonance is caused due to the heavy weight of the rotor. done
clear
View Solution play_arrow
question_answer 16)
Critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in:
A)
Transverse vibrations done
clear
B)
Torsional vibrations done
clear
C)
Longitudinal vibrations done
clear
D)
Longitudinal vibrations provided the shaft is vertical. done
clear
View Solution play_arrow
question_answer 17)
In a automobile service station, an automobile is in a lifted up position by means of a hydraulic jack. A person working in the service station gave a tap to one rear wheel and made it rotate by one revolution. The rotation of another rear wheel is:
A)
Zero done
clear
B)
Also one revolution in the same direction done
clear
C)
Also one revolution but in the opposite direction done
clear
D)
unpredictable done
clear
View Solution play_arrow
question_answer 18)
In the statement "an eccentric mass rotating a 3000 rpm will create X times more unbalanced force than 50% of the same mass rotating at 300 rpm", 'X' stands for:
A)
10 done
clear
B)
50 done
clear
C)
100 done
clear
D)
200 done
clear
View Solution play_arrow
question_answer 19)
A machine of 100 kg mass has a 20 kg rotor with 0.5 mm eccentricity. The mounting springs have stiffness 85 kN/m and damping is negligible. If the operating speed is \[20\pi \] rad/and the unit is constrained to move vertically, the dynamic amplitude of the machine will be:
A)
\[0.170\times {{10}^{-\,4}}m\] done
clear
B)
\[1.000\times {{10}^{-\,4}}m\] done
clear
C)
\[1.274\times {{10}^{-\,4}}m\] done
clear
D)
\[2.540\times {{10}^{-\,4}}m\] done
clear
View Solution play_arrow
question_answer 20)
Match the List I(Force transmissibility) with List II (frequency ratio) and select the correct answer using the codes given below the Lists:
List-I (Force transmissibility) List-II (Frequency ratio) A. 1 1. \[\frac{\omega }{{{\omega }_{n}}}>\sqrt{2}\] B. Less than 1 2. \[\frac{\omega }{{{\omega }_{n}}}=\sqrt{2}\] C. Greater than 1 3. \[\frac{\omega }{{{\omega }_{n}}}>>\sqrt{2}\] D. Tending to zero 4. \[\frac{\omega }{{{\omega }_{n}}}<\sqrt{2}\]
Codes:
A)
A\[\to \]1, B\[\to \]2, C\[\to \]3, D\[\to \]4 done
clear
B)
A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]3 done
clear
C)
A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 done
clear
D)
A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 done
clear
View Solution play_arrow
question_answer 21)
The equation of motion for a single degree of freedom system with viscous damping is: \[4\ddot{x}+9\dot{x}+16x=0.\] The damping ratio of the system is:
A)
\[\frac{9}{128}\] done
clear
B)
\[\frac{9}{16}\] done
clear
C)
\[\frac{9}{8\sqrt{2}}\] done
clear
D)
\[\frac{9}{8}\] done
clear
View Solution play_arrow
question_answer 22)
The critical speed of a rotating shaft depends
A)
Mass done
clear
B)
Stiffness done
clear
C)
Mass and stiffness done
clear
D)
Mass, stiffness and eccentricity. done
clear
View Solution play_arrow
question_answer 23)
Two heavy rotating masses are connected by shafts of length \[{{l}_{1}},{{l}_{2}}\] and \[{{l}_{3}}\] and the corresponding diameters are island (/3.This system is reduced to a torsionally equivalent system having uniform diameter \[{{d}_{1}}\] of the shaft. The equivalent length of the shaft is equal to:
A)
\[{{l}_{1}}+{{l}_{2}}+{{l}_{3}}\] done
clear
B)
\[\frac{{{l}_{1}}+{{l}_{2}}+{{l}_{3}}}{3}\] done
clear
C)
\[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{3}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{3}}\] done
clear
D)
\[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{4}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{4}}\] done
clear
View Solution play_arrow
question_answer 24)
If a mass 'm' oscillates on a spring having a mass \[{{m}_{s}}\] and stiffness ?k?, then the natural frequency of the system is given by:
A)
\[\sqrt{\frac{k}{m+\frac{{{m}_{s}}}{3}}}\] done
clear
B)
\[\sqrt{\frac{k}{\frac{m}{3}+{{m}_{s}}}}\] done
clear
C)
\[\sqrt{\frac{3k}{m+{{m}_{s}}}}\] done
clear
D)
\[\sqrt{\frac{k}{m+{{m}_{s}}}}\] done
clear
View Solution play_arrow
question_answer 25)
Match List-I with List-II and select the correct answer using the codes given below the lists:
List-I List-II A. Node and mode 1. Geared vibration B. Equivalent inertia 2. Damped-free vibration C. Log decrement 3. Forced vibration D. Resonance 4. Multi-rotor vibration
Codes:
A)
A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]2 done
clear
B)
A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done
clear
C)
A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done
clear
D)
A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done
clear
View Solution play_arrow
question_answer 26)
The natural frequency of transverse vibration of a massless beam of length L having a mass m attached at its midspan is given by: (El is the flexural rigidity of the beam)
A)
\[{{\left( \frac{m{{l}^{3}}}{48EI} \right)}^{\frac{1}{2}}}\text{rad/s}\] done
clear
B)
\[{{\left( \frac{48m{{l}^{3}}}{EI} \right)}^{\frac{1}{2}}}\text{rad/s}\] done
clear
C)
\[{{\left( \frac{48EI}{m{{L}^{3}}} \right)}^{\frac{1}{2}}}\text{rad/s}\] done
clear
D)
\[{{\left( \frac{3EI}{m{{L}^{3}}} \right)}^{\frac{1}{2}}}\text{rad/s}\] done
clear
View Solution play_arrow
question_answer 27)
If a spring-mass-dashpot system is subjected to excitation by a constant harmonic force, then at resonance, its amplitude of vibration will be:
A)
Infinity done
clear
B)
Inversely proportional to damping done
clear
C)
Directly proportional to damping done
clear
D)
Decreasing exponentially with time done
clear
View Solution play_arrow
question_answer 28)
In a forced vibration with viscous damping, maximum amplitude occurs when forced frequency is:
A)
Equal to natural frequency done
clear
B)
Slightly less than natural frequency done
clear
C)
Slightly greater than natural frequency done
clear
D)
Zero done
clear
View Solution play_arrow
question_answer 29)
The value of the natural frequency obtained by Rayleigh's method:
A)
Is always greater than the actual fundamental frequency done
clear
B)
Is always less than the actual fundamental frequency done
clear
C)
Depends upon the initial deflection curve chosen and may be greater than or less than the actual fundamental frequency done
clear
D)
Is independent of the initial deflection curve chosen. done
clear
View Solution play_arrow
question_answer 30)
In a multi-rotor system of torsional vibration maximum number of nodes that can occur is:
A)
Two done
clear
B)
Equal to the number of rotor plus one done
clear
C)
Equal to the number of rotors done
clear
D)
Equal to the number of rotors minus one done
clear
View Solution play_arrow
question_answer 31)
A rotating shaft carries a flywheel which overhangs on the bearing as a cantilever. If this flywheel weight is reduced to half of its original weight, the whirling speed will:
A)
Be double done
clear
B)
Increase by \[\sqrt{2}\] times done
clear
C)
Decrease by \[\sqrt{2}\] times done
clear
D)
Be half done
clear
View Solution play_arrow
question_answer 32)
The damping force in forced vibrations with reference to spring force:
A)
Leads by \[90{}^\circ \] done
clear
B)
Lags by \[90{}^\circ \] done
clear
C)
Leads by \[180{}^\circ \] done
clear
D)
Lags by \[180{}^\circ \] done
clear
View Solution play_arrow
question_answer 33)
Match List-I with List-II and select the correct answer using the codes given below the Lists:
List-I List-II A. 6 d.o.f. system 1. Vibrating beam B. 1 d.o.f. system 2. Vibration absorber C. 2 d.o.f. system 3. A rigid body in space D. Multi d.o.f. system 4. Pure rolling of a cylinder
Codes:
A)
A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]5 done
clear
B)
A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done
clear
C)
A\[\to \]3, B\[\to \]2, C\[\to \]4, D\[\to \]1 done
clear
D)
A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done
clear
View Solution play_arrow
question_answer 34)
A shaft carries a weight W at the centre. The CG of the weight is displaced by an amount e from the axis of the rotation. If 'y is the additional displacement of the CG from the axis of rotation due to the centrifugal force, then the ratio of y to e (where \[{{\omega }_{c}}\] is the critical speed of shaft and \[\omega \] is the angular speed of shaft) is given by:
A)
\[\frac{1}{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}+1}\] done
clear
B)
\[\frac{1}{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}-1}\] done
clear
C)
\[{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}+1\] done
clear
D)
\[\frac{\omega }{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}-1}\] done
clear
View Solution play_arrow
question_answer 35)
When a vehicle travels on a rough road whose undulations can be assumed to be sinusoidal, the resonant conditions of the base-excited vibrations, are determined by the:
A)
Mass of the vehicle, stiffness of the suspension spring, speed of the vehicle, wavelength of the roughness curve done
clear
B)
Speed of the vehicle only done
clear
C)
Speed of the vehicle and the stillness of the suspension spring done
clear
D)
Amplitude of the undulations done
clear
View Solution play_arrow
question_answer 36)
During torsional vibration of a shaft, the node is characterized by the:
A)
Maximum angular velocity done
clear
B)
Maximum angular displacement done
clear
C)
Maximum angular acceleration done
clear
D)
Zero angular displacement done
clear
View Solution play_arrow
question_answer 37)
A rod of uniform diameter is suspended from one of its ends in vertical plane. The mass of the rod is 'm' and length T, the natural frequency of this rod in Hz for small amplitude is:
A)
\[\frac{1}{2\pi }\sqrt{\frac{g}{l}}\] done
clear
B)
\[\frac{1}{2\pi }\sqrt{\frac{g}{3l}}\] done
clear
C)
\[\frac{1}{2\pi }\sqrt{\frac{2g}{3l}}\] done
clear
D)
\[\frac{1}{2\pi }\sqrt{\frac{3g}{2l}}\] done
clear
View Solution play_arrow
question_answer 38)
The mass moment of inertia of the two motors in a two rotor system arc \[100\,\,kg.{{m}^{2}}\] and \[10\,\,kg.{{m}^{2}}.\] the length of the shaft of uniform diameter between the rotors is 110 cm. The distance of node from the rotor of lower moment of inertia is:
A)
80 cm done
clear
B)
90 cm done
clear
C)
100 cm done
clear
D)
110 cm done
clear
View Solution play_arrow
question_answer 39)
A shaft of 50 mm diameter and 1 m length carries a disc which has mass eccentricity equal to 190 microns. The displacement of the shaft at a speed which is 90% of critical speed in microns is:
A)
810 done
clear
B)
900 done
clear
C)
800 done
clear
D)
820 done
clear
View Solution play_arrow
question_answer 40)
What is the number of nodes in a shalt carrying three rotors?
A)
Zero done
clear
B)
2 done
clear
C)
3 done
clear
D)
4 done
clear
View Solution play_arrow
question_answer 41)
\[\frac{{{\partial }^{2}}u}{\partial {{t}^{2}}}={{c}^{2}}\frac{{{\partial }^{2}}u}{\partial {{t}^{2}}}\] represents the equation for:
A)
Vibration of a stretched string done
clear
B)
Motion of a projectile in a gravitational field done
clear
C)
Heat flow in thin rod done
clear
D)
Oscillation of a simple pendulum done
clear
View Solution play_arrow
question_answer 42)
The natural frequency of an undamped vibrating system is 100 rad/s. A damper with a damping factor of 0.8 is introduced into the system. The frequency of vibration of the damped system, in rad/s, is:
A)
60 done
clear
B)
75 done
clear
C)
80 done
clear
D)
100 done
clear
View Solution play_arrow
question_answer 43)
A mass m attached to a light spring oscillates with a period of 2 sec. If the mass is increased by 2 kg, the period increases by 1 sec. The value ofwis:
A)
1kg done
clear
B)
1.6 kg done
clear
C)
2 kg done
clear
D)
2.4 kg done
clear
View Solution play_arrow
question_answer 44)
High damping reduces the transmissibility if the non-dimensional frequency ratio \[\omega /{{\omega }_{n}}(\omega =forcing\,\,frequency,\,\,{{\omega }_{n}}=natural\text{ }frequency):\]
A)
Is less than \[\sqrt{2}\] done
clear
B)
is greater than \[\sqrt{2}\] done
clear
C)
Is less than \[\frac{1}{\sqrt{2}}\] done
clear
D)
is greater than \[\frac{1}{\sqrt{2}}\] done
clear
View Solution play_arrow
question_answer 45)
For lightly damped heavy rotor systems, resonance occurs when the forcing co is equal to: Where \[{{\omega }_{cr}}\] is the critical speed.
A)
\[2\,\,{{\omega }_{cr}}\] done
clear
B)
\[\sqrt{2}\,\,{{\omega }_{cr}}\] done
clear
C)
\[{{\omega }_{cr}}\] done
clear
D)
\[\frac{1}{2}\,\,{{\omega }_{cr}}\] done
clear
View Solution play_arrow
question_answer 46)
The silencer of an internal combustion engine:
A)
Reduces noise done
clear
B)
Decreases brake specific fuel consumption (BSFC) done
clear
C)
Increases BSFC done
clear
D)
Has no effect on its efficiency done
clear
View Solution play_arrow
question_answer 47)
The deflection of a spring with 20 active turns under a load of 1000 N is 10 mm. The spring is made-into two pieces each of 10 active coils and placed in parallel under the same load. The deflection of this system is:
A)
20 mm done
clear
B)
10 mm done
clear
C)
5 mm done
clear
D)
2.5 mm done
clear
View Solution play_arrow
question_answer 48)
A flexible rotor-shaft system comprises of a 10 kg rotor disc placed in the middle of a massless shaft of diameter 30 mm and length 500 mm between bearings (shaft is being taken massless as the equivalent of the shaft, is included in the rotor mass) the ends. The bearings are assumed to simulate a supported boundary conditions. The shaft is made of steel for which the value of \[E=2.1\times {{10}^{11}}\]Pa. what is the critical speed of rotation of the shaft?
A)
60 Hz done
clear
B)
90 Hz done
clear
C)
135 Hz done
clear
D)
180 Hz done
clear
View Solution play_arrow
question_answer 49)
A vibrating machine is isolated from the floor using springs. If the ratio of excitation frequency of vibration of machine to the natural frequency of the isolation system is equal to 0.5, the transmissibility of ratio of isolation is:
A)
\[\frac{1}{2}\] done
clear
B)
\[\frac{3}{4}\] done
clear
C)
\[\frac{4}{3}\] done
clear
D)
2 done
clear
View Solution play_arrow
question_answer 50)
For steady flow through an insulated horizontal constant diameter pipe, this property remains constant
A)
Enthalpy done
clear
B)
Internal energy done
clear
C)
Entropy done
clear
D)
Volume done
clear
View Solution play_arrow
question_answer 51)
100 kJ of energy is transferred from a heat reservoir at 1000 K to a heat reservoir at 500 K. The ambient temperature is 300 K. The loss of available energy due to heat transfer process is:
A)
20 kJ done
clear
B)
30 kJ done
clear
C)
40 kJ done
clear
D)
50 kJ done
clear
View Solution play_arrow
question_answer 52)
A shaft, supported on two bearings at its ends, carries two flywheels 'L' apart. Mass moment of inertia of the two flywheels are \[{{l}_{a}}\] and \[{{l}_{b}}\] I being the polar moment of inertia of cross-sectional area of inertia of shaft. Distance \[{{l}_{a}}\] of the node of torsional vibration of the shaft from the flywheel la is \[{{l}_{a}}\] given by:
A)
\[{{l}_{a}}=\frac{L{{l}_{b}}}{{{I}_{a}}+{{I}_{b}}}\] done
clear
B)
\[{{l}_{a}}=\frac{L{{l}_{a}}}{{{I}_{a}}+{{I}_{b}}}\] done
clear
C)
\[{{l}_{a}}=\frac{L{{l}_{b}}}{{{I}_{a}}+{{I}_{b}}-1}\] done
clear
D)
\[{{l}_{a}}=\frac{L{{l}_{a}}}{{{I}_{a}}+{{I}_{b}}-1}\] done
clear
View Solution play_arrow
question_answer 53)
The transmitted force through a mass-spring damper system will be greater than that transmitted through rigid supports for all values of-damping factors, if the frequency ratio \[\left( \frac{\omega }{{{\omega }_{n}}} \right)\] is:
A)
More than \[\sqrt{2}\] done
clear
B)
less than \[\sqrt{2}\] done
clear
C)
Equal to one done
clear
D)
less than one done
clear
View Solution play_arrow
question_answer 54)
In a forced vibrations with viscous damping, maximum amplitude occurs when the forced frequency is:
A)
Equal to natural frequency done
clear
B)
Slightly less than natural frequency done
clear
C)
Slightly greater than natural frequency done
clear
D)
Zero. done
clear
View Solution play_arrow
question_answer 55)
The rotor of a turbine is generally rotated at:
A)
The critical speed done
clear
B)
A speed much below the critical speed done
clear
C)
A speed much above the critical speed done
clear
D)
A speed having no relation to critical speed done
clear
View Solution play_arrow
question_answer 56)
A reed type tachometer uses the principle of:
A)
Torsional vibration done
clear
B)
Longitudinal vibration done
clear
C)
Transverse vibration done
clear
D)
Damped free vibration done
clear
View Solution play_arrow
question_answer 57)
A viscous damping system with free vibrations will be critically damped if the damping factor is:
A)
zero done
clear
B)
less than one done
clear
C)
Equal to one done
clear
D)
greater than one done
clear
View Solution play_arrow
question_answer 58)
In a simple spring mass vibrating system, the natural frequency \[{{\omega }_{n}}\] of the system is (k is spring stiffness m is mass and \[{{m}_{s}}\] is spring mass):
A)
\[\sqrt{\frac{k}{m-\frac{{{m}_{s}}}{3}}}\] done
clear
B)
\[\sqrt{\frac{k}{m+\frac{{{m}_{s}}}{3}}}\] done
clear
C)
\[\sqrt{\frac{k}{m+3{{m}_{s}}}}\] done
clear
D)
\[\sqrt{\frac{k}{m-3{{m}_{s}}}}\] done
clear
View Solution play_arrow
question_answer 59)
Consider the following methods:
1. Energy method 2. Equilibrium method 3. Rayleigh's method.
Which of these methods can be used for determining the natural frequency of the free vibrations?
A)
1 and 2 done
clear
B)
1, 2 and 3 done
clear
C)
1 and 3 done
clear
D)
2 and 3 done
clear
View Solution play_arrow
question_answer 60)
Consider the following statements:
1. In forced vibrations the body vibrates under the influence of an applied force. 2. In damped vibrations amplitude reduces over every cycle of vibration 3. In torsional vibrations the disc moves parallel to the axis of shaft. 4. in transverse vibrations the particles of the shaft moves approximately perpendicular to the axis of the shaft.
Which of these statements are correct?
A)
1, 2 and 3 done
clear
B)
1, 3 and 4 done
clear
C)
2, 3 and 4 done
clear
D)
1, 2 and 4 done
clear
View Solution play_arrow
question_answer 61)
Whirling speed of shaft is the speed at which:
A)
Shaft tends to vibrate in longitudinal direction done
clear
B)
Torsional vibrations occur done
clear
C)
Shaft tends to vibrate vigorously in transverse direction done
clear
D)
Combination of transverse and longitudinal vibration occurs. done
clear
View Solution play_arrow
question_answer 62)
A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is:
A)
5367 rpm done
clear
B)
6000 rpm done
clear
C)
9360 rpm done
clear
D)
12000 rpm done
clear
View Solution play_arrow
question_answer 63)
In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as:
A)
Critical damping ratio done
clear
B)
Damping factor done
clear
C)
Logarithmic decrement done
clear
D)
Magnification factor done
clear
View Solution play_arrow
question_answer 64)
Consider the following statements: Two rotors mounted on a single shaft can be considered to be equivalent to a geared-shaft system having two rotors provided
1. The kinetic energy of the equivalent system is equal to that of the original system. 2. The strain energy of the equivalent system is equal to that of the original system. 3. The shaft diameters of the two systems are equal.
Which of these statements are correct?
A)
1, 2 and 3 done
clear
B)
1 and 2 done
clear
C)
2 and 3 done
clear
D)
1 and 3 done
clear
View Solution play_arrow
question_answer 65)
A spring-mass suspension has a natural frequency of 40 rad/s. What is the damping ratio required if it is desired to reduce this frequency to 20 rad/s by adding a damper to it?
A)
\[\frac{\sqrt{3}}{2}\] done
clear
B)
\[\frac{1}{2}\] done
clear
C)
\[\frac{1}{\sqrt{2}}\] done
clear
D)
\[\frac{1}{4}\] done
clear
View Solution play_arrow
question_answer 66)
Transmissibility is unity at two points. Which one of the following is true for these two points?
A)
\[\frac{\omega }{{{\omega }_{n}}}\] is zero and \[\sqrt{3}\] for all values of damping done
clear
B)
\[\frac{\omega }{{{\omega }_{n}}}\] is zero and \[\sqrt{2}\] for all values of damping done
clear
C)
\[\frac{\omega }{{{\omega }_{n}}}\] is unity and 2 for all values of damping done
clear
D)
\[\frac{\omega }{{{\omega }_{n}}}\] is unity and \[\sqrt{3}\] for all values of damping. done
clear
View Solution play_arrow
question_answer 67)
Suppose two rotors with inertias \[{{l}_{1}}\] and \[{{l}_{2}}\] on shafts of Length \[{{l}_{1}}\] and \[{{l}_{2}}\] respectively, are connected by gears such that the speed of the \[{{l}_{2}}\] rotor is always G times that of the \[{{l}_{2}}\] rotor. This system may, for vibration analysis, he treated as being on one shaft (integral with \[{{i}_{1}}\]) if:
A)
\[{{l}_{1}}\] is changed to \[{{G}^{2}}{{I}_{1}}\] done
clear
B)
\[{{I}_{2}}\] is changed to \[{{G}^{2}}{{I}_{2}}\] done
clear
C)
\[{{I}_{1}}\] is changed to \[{{\text{I}}_{\text{1}}}\text{/}{{\text{G}}^{\text{2}}}\] done
clear
D)
\[{{I}_{2}}\] is changed to \[{{\text{I}}_{2}}\text{/}{{\text{G}}^{\text{2}}}\] done
clear
View Solution play_arrow
question_answer 68)
Two rotors A and B are connected to the two ends of a shaft of uniform diameter. The mass moment of inertia of rotor A about the axis of the shaft is four times that of B. If the length of the shaft is 1 m and C is the position of node for torsional vibrations, then what is the length of AC?
A)
1/5 m done
clear
B)
4/5 m done
clear
C)
1/25 m done
clear
D)
16/25 m done
clear
View Solution play_arrow
question_answer 69)
Which one of the following is realized by hydraulic dashpot shock absorbers?
A)
Viscous damping done
clear
B)
Structural damping done
clear
C)
Coulomb damping done
clear
D)
spring damping done
clear
View Solution play_arrow
question_answer 70)
Which one of the following is the correct statement? Transmissibility is denned as the ratio of the:
A)
Force applied to the machine to the force transmitted to the foundation done
clear
B)
Force transmitted to the foundation to the force applied to the machine done
clear
C)
Force applied to the machine to the vector sum of spring forces done
clear
D)
Damping forces to the spring forces. done
clear
View Solution play_arrow
question_answer 71)
Which one of the following is correct for a shaft carrying two rotors at its ends?
A)
It has no node done
clear
B)
It has one node done
clear
C)
It has two nodes done
clear
D)
It has three nodes done
clear
View Solution play_arrow
question_answer 72)
A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 cycles/sec and 200 cycles/sec respectively. The lowest critical speed is:
A)
5367 rpm done
clear
B)
6000 rpm done
clear
C)
9360 rpm done
clear
D)
12,000 rpm done
clear
View Solution play_arrow
question_answer 73)
A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaded mode, it has a frequency of vibration of 10 radians second. When the shaft is rotated a 300 revolutions per minute, it will whirl with a radius of:
A)
2 mm done
clear
B)
225 mm done
clear
C)
2.50 mm done
clear
D)
3.00 mm done
clear
View Solution play_arrow
question_answer 74)
A uniform cantilever beam undergoes transverse vibrations. The number of natural frequencies associated with the beam is:
A)
1 done
clear
B)
10 done
clear
C)
100 done
clear
D)
infinite done
clear
View Solution play_arrow
question_answer 75)
Coulomb damping results from which one of the following?
A)
Dry friction between moving parts done
clear
B)
Drag between a moving body and the fluid environment done
clear
C)
Internal friction within a material done
clear
D)
Radiation of energy into the environmentl. done
clear
View Solution play_arrow
question_answer 76)
Consider the following statements:
1. When frequency ratio is < 2, the force transmitted to the foundation is more than the exciting force. 2. When frequency ratio is > 2, the force transmitted to the foundation increases and the damping is decreased. 3. The analysis of base excited vibrations is similar to that of forced vibrations.
Which of these statements are correct?
A)
1 and 2 done
clear
B)
2 and 5 done
clear
C)
1 and 3 done
clear
D)
1, 2 and 3 done
clear
View Solution play_arrow
question_answer 77)
Consider the following statements:
1. Critical or whirling speed of the shaft is the speed at which it tends to vibrate violently in the transverse direction. 2. To find the natural frequency of a shaft carrying several loads, the energy method gives approximate results. 3. Dunkerley's method gives accurate results of the natural frequency of a shaft carrying several loads.
Which of these statements is/are correct?
A)
1 only done
clear
B)
2 and 3 done
clear
C)
1 and 3 done
clear
D)
1, 2 and 3 done
clear
View Solution play_arrow
question_answer 78)
For a single degree of freedom damped system, transmissibility is less than 1 if frequency ratio is:
A)
\[Equal\,\,to\,\,1\] done
clear
B)
<1 done
clear
C)
\[<\sqrt{2}\] done
clear
D)
\[>\sqrt{2}\] done
clear
View Solution play_arrow
question_answer 79)
For a harmonically excited single degree of freedom viscous damped system, which one of the following is correct?
A)
Inertia force leads damping force by \[90{}^\circ \] while damping force leads spring force by\[90{}^\circ \]. done
clear
B)
Spring force leads damping force by \[90{}^\circ \] while damping force leads inertia force by\[180{}^\circ \]. done
clear
C)
Spring force and damping force are in phase, and inertia force leads them by \[90{}^\circ \] done
clear
D)
Spring force and inertia force are in phase, and damping force leads them by \[90{}^\circ \] done
clear
View Solution play_arrow
question_answer 80)
In a viscously damped vibratory system with harmonic excitation, if \[{{\omega }_{1}}\] and \[{{\omega }_{2}}\] are the half power points, \[{{\omega }_{n}}\] is the natural frequency and \[\zeta \] is the damping factor, which one of the following is correct?
A)
\[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}\] done
clear
B)
\[\frac{{{\omega }_{2}}+{{\omega }_{1}}}{{{\omega }_{n}}}=\zeta \] done
clear
C)
\[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}={{\zeta }^{2}}\] done
clear
D)
\[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}=\zeta \] done
clear
View Solution play_arrow
question_answer 81)
Match List-I with List-II regarding a body party submerged in a liquid and select the correct answer using the codes given below the lists:
List-I List-II A. Centre of pressure 1. Point of application of the weight of displaced liquid B. Centre of gravity 2. Point about which the body starts oscillating when tilted by a small angle C. Centre of buoyancy 3. Point of application of hydrostatic pressure D. Metacentre 4. Point of application of the weight of the body
Codes:
A)
A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 done
clear
B)
A\[\to \]4, B\[\to \]3, C\[\to \]2, D\[\to \]1 done
clear
C)
A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2 done
clear
D)
A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done
clear
View Solution play_arrow
question_answer 82)
If a piece of metal having a specific gravity of 13.6 is placed in mercury of specific gravity 13.6, then:
A)
The metal piece will sink to the bottom done
clear
B)
The metal piece will simply float over the mercury with no immersion done
clear
C)
The metal piece will be immersed in mercury by half done
clear
D)
The whole of the metal piece will be immersed with its top surface just at mercury level done
clear
View Solution play_arrow
question_answer 83)
A bucket of water hangs with a spring balance. If an iron piece is suspended into water from another support without touching the sides of the bucket, the spring balance will show:
A)
An increased reading done
clear
B)
A decreased reading done
clear
C)
No change in reading done
clear
D)
Increased or decreased reading depending on the depth of immersion done
clear
View Solution play_arrow
question_answer 84)
The least radius of gyration of a ship is 9 m and the metacentric height is 750 mm. The time period of oscillation of the ship is:
A)
42.41 s done
clear
B)
75.4 s done
clear
C)
20.85 s done
clear
D)
85 s done
clear
View Solution play_arrow
question_answer 85)
If the surface tension of water-air interface is 0.073 N/m, the gauge pressure inside a rain drop of 1 mm diameter will be:
A)
\[0.146\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done
clear
B)
\[0.73\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done
clear
C)
\[146\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done
clear
D)
\[292\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done
clear
View Solution play_arrow
question_answer 86)
Newton's law of viscosity depends upon the:
A)
Stress and strain in a fluid done
clear
B)
Shear stress, pressure and velocity done
clear
C)
Shear stress and rate of strain done
clear
D)
Viscosity and shear stress done
clear
View Solution play_arrow
question_answer 87)
The critical speed of a uniform shaft with a rotor at the centre of the span can be reduced by:
A)
Reducing the shaft length done
clear
B)
Reducing the rotor mass done
clear
C)
Increasing the rotor mass done
clear
D)
Increasing the shaft diameter done
clear
View Solution play_arrow
question_answer 88)
Match List-I (Surfaces with Orientations) with List-II (Equivalent Emissivity) and select the correct answer using the codes given below the lists:
List I (Surfaces with orientations) List-II (Equivalent Emissivity) A. Infinite parallel planes 1. \[{{\in }_{1}}\] B. Body 1 completely enclosed by body 2 but body 1 is very small 2. \[\frac{1}{\frac{1}{{{\in }_{1}}}+\frac{1}{{{\in }_{2}}}-1}\] C. Radiation exchange between two small gray bodies 3. \[\frac{1}{\frac{1}{{{\in }_{1}}}+\left( \frac{{{A}_{1}}}{{{A}_{2}}} \right)\left( \frac{1}{{{\in }_{2}}}-1 \right)}\] D. Two concentric cylinders with large lengths 4. \[{{\in }_{1}}.{{\in }_{2}}\]
Codes:
A)
A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2 done
clear
B)
A\[\to \]2, B\[\to \]4, C\[\to \]1, D\[\to \]3 done
clear
C)
A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]3 done
clear
D)
A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2 done
clear
View Solution play_arrow
question_answer 89)
Two spheres A and B of same material have radii 1 m and 4 m and temperature 4000 K and 2000 K respectively. Which one of the following statements is correct? The energy radiated by sphere A is:
A)
Greater than that of sphere B done
clear
B)
Less than that of sphere B done
clear
C)
Equal to that of sphere B done
clear
D)
Equal to double that of sphere B done
clear
View Solution play_arrow
question_answer 90)
For an opaque plane surface, the irradiation, radiosity and emissive power are respectively 20, 12 and \[10\,\,\text{W/}{{\text{m}}^{\text{2}}}.\] what is the emissivity of the surface?
A)
0.2 done
clear
B)
0.4 done
clear
C)
0.8 done
clear
D)
1.0 done
clear
View Solution play_arrow
question_answer 91)
Two long parallel surfaces, each of emissivity 0.7, are maintained at different temperatures and accordingly have radiation exchange between them. It is desired to reduce 75% of this radiant heat transfer by inserting thin parallel shields of equal emissivity (0.7) on both sides. What would be the number of shields?
A)
1 done
clear
B)
2 done
clear
C)
3 done
clear
D)
4 done
clear
View Solution play_arrow
question_answer 92)
The earth receives at its surface radiation from the sun at the rate of \[1400\,\,\text{W/}{{\text{m}}^{\text{2}}}.\] the distance of centre of sun from the surface of earth is \[1.5\times {{10}^{11}}m\] and the radius of sun is \[7.0\times {{10}^{8}}M.\] what is approximately the surface temperature of the sun treating the sun as a black body?
A)
3650 K done
clear
B)
4500 K done
clear
C)
5800 K done
clear
D)
6150 K done
clear
View Solution play_arrow
question_answer 93)
A composite plane wall is made up of two different materials of the same thickness and having thermal conductivities of \[{{k}_{1}}\] and \[{{k}_{2}}\] respectively. The equivalent thermal conductivity of the slab is:
A)
\[{{k}_{1}}+{{k}_{2}}\] done
clear
B)
\[{{k}_{1}}{{k}_{2}}\] done
clear
C)
\[\frac{{{k}_{1}}+{{k}_{2}}}{{{k}_{1}}{{k}_{2}}}\] done
clear
D)
\[\frac{2{{k}_{1}}{{k}_{2}}}{{{k}_{1}}+{{k}_{2}}}\] done
clear
View Solution play_arrow
question_answer 94)
A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermo- conductivity of 05 W/m.K. The outside surface convective heat transfer coefficient is 10 W/m.K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current carrying capacity of the wire will:
A)
Increase done
clear
B)
Decrease done
clear
C)
Remain the same done
clear
D)
Vary depending upon the electric conductivity of the wire. done
clear
View Solution play_arrow
question_answer 95)
For the fully developed laminar flow and the transfer in a uniformly heated long circular tube, if the velocity is doubled and the tube diameter is halved, the heat transfer coefficient will be:
A)
Double of the original value done
clear
B)
Half of the original value done
clear
C)
Same as before done
clear
D)
Four times of the original value. done
clear
View Solution play_arrow
question_answer 96)
For an air conditioning plant above 300 ton, which one of the following system would normally he preferred?
A)
Ammonia reciprocating compressor done
clear
B)
Centrifugal Chiller done
clear
C)
Absorption refrigeration system done
clear
D)
Hermetic compressor done
clear
View Solution play_arrow
question_answer 97)
Fresh air intake (air change per hour) recommended for ventilation purposes in the air conditioning system of an office building is:
A)
1/2 done
clear
B)
3/2 done
clear
C)
9/2 done
clear
D)
25/2 done
clear
View Solution play_arrow
question_answer 98)
Air refrigeration cycle is used in:
A)
Commercial refrigerators done
clear
B)
Domestic refrigerators done
clear
C)
Gas liquefaction done
clear
D)
Air-conditioning done
clear
View Solution play_arrow
question_answer 99)
The flash chamber in a single stage simple vapour compression cycle:
A)
Increase the refrigerating effect done
clear
B)
Decreases the refrigerating effect done
clear
C)
Increases the work of compression done
clear
D)
Has no effect on refrigerating effect done
clear
View Solution play_arrow
question_answer 100)
Consider the following statements:
In a vapour compression system, a thermometer placed in the liquid line can indicate whether the: 1. Refrigerant flow is too low 2. Water circulation is adequate. 3. Condenser is fouled. 4. Pump is functioning properly.
Of these statement:
A)
1, 2 and 3 are correct done
clear
B)
1, 2 and 4 are correct done
clear
C)
1, 3 and 4 are correct done
clear
D)
2, 3 and 4 are correct done
clear
View Solution play_arrow
question_answer 101)
Match List-I with List-II and select the correct answer using the codes given below the Lists.
List-I List-II A. Bell Column refrigeration 1. Compressor B. Vapour compression refrigeration 2. Generator C. Absorption refrigeration 3. Flash chamber D. Jet refrigeration 4. Expansion cylinder
Codes:
A)
A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]2 done
clear
B)
A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done
clear
C)
A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done
clear
D)
A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done
clear
View Solution play_arrow
question_answer 102)
The maximum COP for the absorption cycle is given by\[({{T}_{c}}=generator\,\,temperature\,\,{{T}_{c}}=environment\,\,temperature,\]\[{{T}_{E}}=refrigerated\,\,space\,\,temperature)\]
A)
\[\frac{{{T}_{E}}({{T}_{G}}-{{T}_{C}})}{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}\] done
clear
B)
\[\frac{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}{{{T}_{E}}({{T}_{G}}-{{T}_{C}})}\] done
clear
C)
\[\frac{{{T}_{C}}({{T}_{G}}-{{T}_{E}})}{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}\] done
clear
D)
\[\frac{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}{{{T}_{C}}({{T}_{G}}-{{T}_{E}})}\] done
clear
View Solution play_arrow
question_answer 103)
In milk chilling plants, the usual secondary refrigerant is:
A)
Ammonia solution done
clear
B)
Sodium Silicate done
clear
C)
Glycol done
clear
D)
Brine done
clear
View Solution play_arrow
question_answer 104)
104. The desirable combination of properties of a refrigerant include :
A)
High specific heat and low specific volume done
clear
B)
High heat transfer coefficient and low latent heat done
clear
C)
High thermal conductivity and low specific volume done
clear
D)
High specific heat and high boiling point. done
clear
View Solution play_arrow
question_answer 105)
Which of the following method(s) is/are adopted in the design of air duct system
1. Velocity reduction method 2. Equal friction method 3. Static regain method.
Select the correct answer using the codes given below: Codes:
A)
1 alone done
clear
B)
1 and 2 done
clear
C)
2 and 3 done
clear
D)
1, 2 and 3 done
clear
View Solution play_arrow
question_answer 106)
To fix the stale point in respect of air-vapour mixtures, three intrinsic properties are needed. Yet, the psychrometric chart requires only two because:
A)
Water vapour is in the superheated state done
clear
B)
The chart is for a given pressure done
clear
C)
The chart is an approximation to true values done
clear
D)
The mixtures can be treated as a perfect gas done
clear
View Solution play_arrow
question_answer 107)
During sensible cooling of air :
A)
Its wet bulb temperature increases and dew point remains constant done
clear
B)
Its wet bulb temperature decreases and the dew point remains constant done
clear
C)
Its wet bulb temperature increases and the dew point decreases done
clear
D)
It wet bulb temperature decreases and dew point increases. done
clear
View Solution play_arrow
question_answer 108)
The expression \[\frac{0.622{{p}_{v}}}{{{p}_{r}}-{{p}_{v}}}\] is used to determine:
A)
Relative humidity done
clear
B)
Specific humidity done
clear
C)
Degree of saturation done
clear
D)
Partial pressure done
clear
View Solution play_arrow
question_answer 109)
The effective temperature is a measure of the combined effects of:
A)
Dry bulb temperature and relative humidity done
clear
B)
Dry bulb temperature and air motion done
clear
C)
Wet bulb temperature and air motion done
clear
D)
Dry bulb temperature, relative humidity and air motion. done
clear
View Solution play_arrow
question_answer 110)
In air-conditioning design for summer months, the condition inside a factory where heavy work in performed as compared to a factory in which light work is performed should have:
A)
Lower dry bulb temperature and lower relative humidity done
clear
B)
Lower dry bulb temperature and higher relative humidity done
clear
C)
Lower dry bulb temperature and same relative humidity done
clear
D)
Same dry bulb temperature and same relative humidity. done
clear
View Solution play_arrow
question_answer 111)
For low by pass factor a cooling coil, the fin spacing and the number of tube rows will be respectively:
A)
High and high done
clear
B)
High and low done
clear
C)
Low and high done
clear
D)
Low and low done
clear
View Solution play_arrow
question_answer 112)
In vapour compression plant, if certain temperature differences are to be maintained in the evaporator and condenser in order to obtain the necessary heat transfer, then the evaporator saturation temperature must be:
A)
Higher than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts done
clear
B)
Low than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts done
clear
C)
Lower than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts done
clear
D)
Higher than the derived cold-region temperature and the condenser saturation temperature must he higher than the available cooling water temperature by sufficient amounts. done
clear
View Solution play_arrow
question_answer 113)
One ton refrigeration is equivalent to:
A)
3.5 kW done
clear
B)
50 kJ/s done
clear
C)
1000 J/min done
clear
D)
1000 kJ/min done
clear
View Solution play_arrow
question_answer 114)
The correct sequence of the given components of a vapour compression refrigerator is:
A)
Evaporator, compressor, condenser and throttle valve done
clear
B)
Condenser, throttle valve, evaporator and compressor done
clear
C)
Compressor, condenser, throttle valve and evaporator done
clear
D)
Throttle valve, evaporator, compressor and condenser done
clear
View Solution play_arrow
question_answer 115)
The coefficient of performance of a refrigerator working on a reversed Carnot cycle is 4 the ratio of the highest absolute temperature to the lowest absolute temperature is:
A)
1.2 done
clear
B)
1.25 done
clear
C)
3.33 done
clear
D)
4 done
clear
View Solution play_arrow
question_answer 116)
When a burnt out hermetic compressor is replaced by a new one it is desirable to include in the system a large drier-cum-strainer also. This is to be placed in:
A)
Liquid line done
clear
B)
Suction line done
clear
C)
Hot gas line done
clear
D)
Discharge line done
clear
View Solution play_arrow
question_answer 117)
A good refrigerant should have:
A)
Large latent heat of vaporization and low operating pressures done
clear
B)
Small latent heat of vaporization and high operating pressures done
clear
C)
Large latent heat of vaporization and large operating pressures done
clear
D)
Small latent heat of vaporization and low operating pressures done
clear
View Solution play_arrow
question_answer 118)
The most common type of absorption system in use in industrial applications is based on the refrigerant absorbent combination of:
A)
Air-Water done
clear
B)
Lithium bromide-air done
clear
C)
Carbon dioxide-Water done
clear
D)
Ammonia-Water done
clear
View Solution play_arrow
question_answer 119)
Solar energy be directly used in:
A)
Vapour compression refrigeration system done
clear
B)
Vapour absorption refrigeration system done
clear
C)
Air refrigeration system done
clear
D)
Jet refrigeration system done
clear
View Solution play_arrow
question_answer 120)
The equation \[\phi =\frac{{{p}_{v}}}{ps}\] is used to calculate the \[({{p}_{v}}=\] partial pressure of water vapour in moist air at a given temperature \[{{p}_{s}}=\] saturation pressure of water vapour at the same temperature)
A)
Relative humidity done
clear
B)
Degree of saturation done
clear
C)
Specific humidity done
clear
D)
Absolute humidity done
clear
View Solution play_arrow